A 3D hybrid simulation study of the electromagnetic field distributions in the lunar wake

► We use a 3D hybrid code to study the electromagnetic distributions in the lunar wake. ► The near-vacuum wake region will produce enhancement of magnetic fields by a factor of 1.4. ► The formation of electric field in the wake boundaries would reach 0.2-0.8 mV/m. ► Asymmetries of the inward diffusions both along and perpendicular to the field lines are observed.